Pump



B. B. HOLMES.

PUMP. APPLICATION FILED SEPT- 3.1919.

1,436,443. at d ov. 21, 1922.

w egeav .n

INVENTOR a? v BY W 'ZECAKATTORNEY Patented New. 21, 1 922. v

BRADFdRD B. HOLMES, 01 THE UNITED STATES ARMY.

PUMP.

Application filed. September 3, 1919. Serial No. 321,352.

. To all whom it may concern:

Be it known that I, BRADFORD HOLMES, a citizen of the United States,major, Coast Artillery, United StatesArmy, stationed at Washington,District of Columbia, have in vented an Improvement iir Pumps, of whichthe following is a specification.

My present invention relates more particularly to compression pumps suchas are used in rconnection with refrigeratingmachines, and moreparticularly to pumps designed to form a part of small refrigeratingmachines of. the compression-extension type adapted to householduse.

Generallystated the pump element of such machines is designed tocompress a'gaseous fluid as, for instance, sulphur-dioxide and to expelit under compressionvinto a condenser where it is liquefied.

. corrugations The well rugations which can rendered practically Forsuch purposes my present invention contemplates a motor-driven pumpwhich}; make leakless by employment of a fl'exible metallic bellowsbetween the pump piston and cylinder. Preferably the dead space betweenthe metallic bellows and the cylinder wall is filled with. oil orglycerine, both for the purpose'of decreasing possibility of leakage ofthe gaseous fluid to be compressed, and also to decrease thecleardesired I may employing a surplus of the oil. The flexible metallicbellows may consist of ametal tube rolled or otherwise formed withcircular or helical convolutions or cor The tube is thin enoughrandithedeep enough and closely enough spaced to give the desired lengthwiseflexibility required to permit full stroke of the pump piston withoutfatiguing the metaL known Fulton sylphon tubes may be employed for thispurpose where circular corrugations are desired, but I also contemplateutilizing tubes with helicaLcorbemade by methods other than thoseemployed by Fulton.

I have discovered that when corrugated tubes, either the circular orhelical type, are

rugations.

; made of suflicient lengthwith respect to the piston stroke, allfatigue of the metal may be avoided and this element of'the' pump immuneto deterioration or wear; that no matter what length of tube is requiredfor this purpose, the dead space thus introduced in the compressionother is the 'glycerine or oil.

cavity can be eliminated by filling said space though the tubes are ofconsiderable length, and very flexible by reason of thinness of walls,depth, corrugation and length ofthe tube, they will automatically tendto maintain a true. cylinder outline with corresponding parts alwaysequidistant from a straight line axis, when arranged so that the highcompression takes effect on the exterior of the tube instead of on theinterior, provided the two ends of the tube are kept parallel with eachother at right angles to and concentric with the axis. This of courserequires that the piston element to which the movable end of the tube issecured, .be rigidly guided for movement in a line parallel with theaxis of said tube.

In my device there are two fluids circulating through the pump circuit.One is the gaseous medium to be compressed, and the The oil is used inthe pump to fill up the dead space, seal in the" valves, to lubricatethem, and to'cut down clearance. This is an important fea ture as itcauses my pump to operate at maximum efliciency and with minimumelectrical consumption. r1 i The degree of compression of the gaseousfluid in my pump may be regulated within wide limits by regulating thesupply of-oil to decrease or increase the clearance. As the clearancecan be decreased to zero, the maximum compression attainable will belimited only by the power applied to the driving mechanism by the motor,any desired lesser degree of compression being attainable by merelyvarying the back pressure on the outlet. Other features of the deviceare automatic lubrication of the pump driving mechanism and motor,silence and neat appearance. Furthermore, the apparatus is notcomplicated, requires no attention, is extremely durable, and not tooexpensive for general use.

The above and other features of my invention may be more fullyunderstood from the following description in connection with theaccompanying drawings, in which Figure 1 is a vertical central sectionin the plane of the axes of pump and drive shaft;

Figure 2 is a plan section of the top casting OIL the line 2-2, Figure1;

flexible coupling. 14, which may be any suitabletype. The worm 13rotates in the bearings 15 and 16 and against the thrust discs 17. heworm engages with and turns the worm wheel 18, whose bearing 19 rotatesin a bushing 20 held in its bed in the base cast- I in 11 by the yoke21.

he worni wheel 18 gives reciprocating motion to the pump piston 22 bymeans of the connecting rod 23. The worm wheel revolves in oil so thatoil is carried 'to the rapidly rotating worm which throws oil I and 27carry piston.

spray about, lubricating the worm and worm wheel bearings, .theconnecting rod bearings and the cylindrical guide 24 for the pump pipe25'With two upright pipes 26 oil to two wicks (not shown) whichlubricate the motor bearings.

. An oil .filler pipe and fittings 28 closed with a wing top plug 29supplies an easy A small method of testing the lubricating oil; level,

and adding additional 'oil when necessary. The entire externallubrication ofthe machine is thus supplied byjpouring .oil' in the inlet28.

Secured to the base casting 11,;isan inter- "mediate casting. 30 Thiscasting contains the supports for worm bearings: 15 and 16,

I cylindrical guide 24. ,for'the' -pump piston,

axis of the tube and are secured .the sliding joint between the coolingwater inlet" '31, cooling water outlet 32, condenser pipe ,bushing 34,and threaded sleeves 33, 33. for the pump cylinder 35 and condensercylinder 36.

The ends of the tube constitutin the flexible metallic bellows 37, arecut 0 squarely at right angles to 7 the main longitudinal by soldermg orother means, one end to the piston element 22 and the other end toclosure for r piston and cylinder elements of the pump. v As beforelinternally extending hermetic stated this bellows may be constructedfrom a metal tube-rolled or otherwise formed with circular or helicalconvolutions deep enough and close enough spaced to give the desiredlengthwise flexibility. I

The piston 22, pump guide 24 and bellows tube 37 are parallel so thatthe movable end of the tube 37 is parallel with the fixed'end allpositions thereof. Hence reciprocat on of the piston requires onlyuniform exlows tube, rather the casting 30, so that said bellows tubeconstitutes'anpansion and contraction ofthe corrugations of the tube ina direction parallel with the tube axis, and the tube is long enough sothat the amount of bending of the metal is, at all points, well withinthe limits of fatigue of the metal. The only other stresses takingeffect on the bellows tube are external pres-., sures applied withperfect uniformity through the oil or other medium filling the spacebetween the bellows tube 37 and cylinder 35. Such pressures, thoughuniformly applied, are not uniformly resisted by the walls of the tube,since the'latter can never be made perfectly uniform .and symmetrical,in construction, particularly as to thick-' ness and resilience 'of thematerial. This might be expected to result in lateral bulging andcrooking of the tube, and it does do so when the pressure is internallyapplied.

I have discovered, however, that when the pressures are externallyapplied any inequalities of the resistances to the pressuresareautomatically compensated for so thatthe net result is not to crookthe tube but, on the contrary, the external pressure will tend tostraighten out crooks in a previously crooked tube. Hence, it will beseen that an important feature of my invention consists in causing thehi h pumping pressures to take effect externa ly of the corrugatedbelthan internally thereof. Approximately uniform atmospheric pressureis maintained within the bellows tube by openings 24 communicating withatmos phere through the base of the engine. These openings also permitaccess of lubricant to the interior of the bellows tube As a reto crookinto engagement either with the piston guide which it surrounds, or withthe piimp cylinder by which it is surrounded.

oreover, if the stralghtening e'flect of the external pressure provesinsuflicient to prevent all contact, such contact as occurs will beslight'and will be unproductive of Wear jsult thereis no tendency of'thebellows tube because of the above described arrangement i for interioras well as the tube. v

The top of pump cylinder 35 is threaded to take the top casting 38. Thetop end of condenser cylinder 36 is beveled, and as exterior lubricationof ,casting 38-.is screwed down on cylinder-35, thebeveled edge fitstightly against it making a water tight joint. The packing rings 39 and40 assist in ensuring that the joint is water tight. 4

The pump cylinder 35, intermediate cast mg 30, and top casting 38, arecarefully threaded and the threads sealed with suitable thread fillingcompound and gaskets so that the joints between the cylinder andcastings are gas tight.

Top casting 38 is supplied with the suctron valve 41, suction valvehousing 42, suction valve closing spring 41, suction valve retainer andspring 45, outlet valve seat 46,

oil settling chamber 47, outlet passage 48, 'ball check valve inlet 49,inlet sealing plug 50, and cooling water outlet 32.

A suction pipe 56 is secured by bushing 43 to the top of the suctionvalve chamber, and a compression conduit which may be a condenser pipe57, is soldered into a hole drilled to meet the outlet passage 48.Suction pipe 56 leads from the source of fluid to be pumped orcondensed, as for instance the evaporator of a refrigerating machine.Pipe 57 is coiled in the chamber between 35 and 36 and may constitutethe condensing element of the refrigerator. Pipe 57 leaves said chamberthrough the bushing 34 and its outlet is controlled by valve 74.

Cooling Water is admitted from the water main to the condenser by pipe58, and the warmed discharged condenser water drips away through pipe59.

Beciprocation of the pump piston '22 causes the oil level in the pumpchamber to rise and fall, sucking in gas through pipe 56 and expellingit under pressure to the pipe 57 where it may be condensed by its.pressure and by being cooled.

As gas is forced out of the pump chamber through valve 44, it will tendto carry a little oil with it. Most of the oil settles out in thechamber 47, and a slight leak in the valve 44, purposely provided for byleaving the hole for the wire valve retainer 45 a little large, allows afew drops of oil to drip back on the suction stroke into the pumpchamber, thus ensuring always a slight excess of oil and, consequently,no clearance.

From the foregoing description it is evident that this invention can becarried out in other forms by the use of other materials and otherfluids than as above described. Therefore, I do not limit myself to thestruc ture or materials described in the preferred form, but include allother forms and materials by which this invention may be realized whichare within the spirit of the invention and Within the scope of myclaims.

What I claim is 1. In a pressure pump apparatus, the

. combination of a pump chamber comprising a cylinder, a piston, and ametallic bellows secured at one end to said cylinder and at the otherend to said piston; inlet and outlet valves, and a liquid fillercompletely filling said pump chamber when tl-e pump piston is at itsnearest point to the cylinder .head.

2. In a pressure pump apparatus, the combination of two relativelymovable pump elements; flexible metallic bellows connecting the same andforming therewith a gas pump chamber; suitableinlet and exhaust valves;and a liquid contained in said pump chamber to reduce the elfectiveclearance.

pump; and a top thereby,

3. In a pressure pump apparatus, the

combination of a pump comprising acylinder element, a piston element anda metallic bellows secured at one end to said cylinder, and at theother. end to -said piston; a liquid filler completely filling said pumpchamber when the piston is at its nearest approach to the cylinder head;an inlet valve, and an outlet valve so constructed as to allow a slightleakage of liquid past saidvalve.

4. In a pressure pump apparatus, the

combination of two relatively movable pump elements; flexible metallicbellows connecting the same and forming therewith a gaspump chamber;suitable inlet and exhaust valves for said chamber; a liquid containedin said pump chamber to minimize the-clearance ;a reservoir beyond thedischarge valve adapted to retain liquid passing the discharge valve;and a minute port leading from said reservoirto said pump cylinder tolead liquid slowly from said reservoir back tosaid pump chamber.

5. In a pressure pump apparatus, in combination, a pump comprising tworelatively movable pump elements and a metal-' lic bellows secured toone of said pump elements at one end and to the other of said elementsat the other end; the arrangement of parts being such that the interiorpump pressures take effect on the exterior of the bellows.

6. In a compressor, the combination of a gas pump having a dischargeleading from its top; a liquid retaining separating-reservoir fed bysaid discharge; a bleed port leading from said reservoir back to saiddischarge from said res-' ervoir. v

7. .A gas compressor comprising a cham-- ber element and a pistonelement and means for relatively moving one with respect to the other,and a flexible metallic bellows secured to and extending between saidelements parallel with the direction of their relative movement andhaving the pressure ,of the compressed gas applied on the exterior ofthe bellows.

8. A gas compressor comprising a-cylin'- I a 115 der, a piston and meansfor guiding it within said cylinder, in combination with a corrugated,longitudinally flexible tube extending within said cylinder and securedat one end to said piston and at the other end over the open end of thecylinder, said tube being coaxial with said cylinder and piston elementsand arranged so that in operation the pressure of the compressed gastakes effect on the exterior of said tube.

9. A gas compressor "comprisinga pump cylinder and, concentrictherewith, a piston guide of substantially smaller diameter and lesslength extending inwardly from one end of said pump cylinder; a pistonguided an approximately cylindrical,

square-ended, thin;walled, deeply-corrugated, longitudinally-flexible,spring metal tube located, in the space between the cylinder andpistonguide secured at one end to the -piston and at the othenend to an'anchorage' surrounding the piston guide openingin such relation as tobe normally without any substantial pressure of sliding contact withadjacent exterior or interior parts of the mechanism and to have gaspressures generated by the compression strokes of the pump taking effecton the exterior of said tube.

10. A gas compressor comprising a pump cylinder and, concentrictherewith, a piston guide of substantially smaller diameter and lesslength extending inwardly from one end of said pump cylinder; a pistonguided thereby, P an approximately cylindrical, square-ended,thin-walled, deeply-corrugated, longitudinall y-flexible, spring metaltube located in the space between the cylinder and piston guide securedat one end to the piston and at the other end to anchorage surroundingthe piston guide opening in such relation as to be normally'without anysubstantial pressure of sliding contact with adjacent exterior orinterior parts of.

the mechanism and to have gas pressures generated by the compressionstrokes of the pump taking effect on the exterior of said tube, andmeans for maintaining the interior of said tube at a much lowerpressure.

11. A gas compressor comprising a pump cylinder and, concentrictherewith, a piston guide of substantially smaller diameter and lesslength extending inwardly from one end of said pump cylinder; a'i pistonguided thereby, an approximately cylindrical, square-ended, thin-walleddeeply-corruinder and gated, longitudinally-flexible; spring metal tubelocated in the space between the cylpiston guide secured at one end tothe piston and at the other end to anchorage surrounding the pistonguide opening in such relation as to be normally without any substantialpressure of sliding contact with adjacent exterior or interior parts ofthe mechanism and to have gas pressures generated by the compressionstrokes of the pump taking effect on the exterior of said tube, andmeans for maintaining the interior of said tube at a much lower pressureand for lubricating said interior; 65

12. A gas compressor comprising a pump cylinder and a piston concentrictherewith, means for reciprocating said piston through an opening in oneend of. said cylinder to varythe volume of compression space within saidcylinder, a suitably valved inlet and outlet for said compression space,an approximately straight, square-headed, thin walled,'circumferentially-corrugated, longitudinally-fie'xible, spring-metaltube located in the space between the cylinder and the pistonreciprocating means, secured at one end to the piston and at the otherend to an anchorage surrounding the opening through which the pistonreciprocating means extends, and'arranged to have the gas pressuresgenerated by the compression strokes of the pump take efiect on theexterior of said tube, the normal length of the tube and the distancebetween the points at Which its ends are secured being very great as.compared with the stroke of the piston. 1

13. A gas compressor comprising a pump cylinder and a piston concentrictherewith, means for reciprocating said piston through an opening in oneend of said cylinder to vary the volume of compression space with- I insaid cylinder, a suitably valved inlet and outlet for said compressionspace, an approximately! straight, square-ended, thin walled,circumferentially-corrugated, longitudinally-flexible, spring-metal tubelocated in the space between the cylinder and the piston reciprocatingmeans, secured at one end to the piston and at the other end to ananchorage surrounding the opening through which the piston reciprocatingmeans extends, and arranged to have the gas pressures generated by thecompression "strokes of the pump take eil'ect on the exterior of saidtube, the normal length of the tube and the distance between the pointsat vwhich its ends are secured being very great as compared with thestroke of the piston, in combination with means for supplying the powerto reciprocate the piston, including a power driven worm. and a wormgear provided with a crank pin adjacent the said opening in the end ofsaid cylinder and the means for translating the crank pin motion intoreciprocating motion of the piston consisting of a link extending fromsaid pin through said opening and connected to the piston at a pointnear the head thereof,

14. A gascompressor comprising a pump cylinder and a piston concentrictherewith, means for reciprocating said piston through an opening in oneend of said cylinder to the piston reciprocating means, secured at oneend to the piston and at the other end to an anchorage surrounding theopening through which the piston reciprocating means extends, andarranged to have the gas pressures generated by the compression strokesof the pump take efi'ect on the exterior of said tube, the normal lengthof the tube and the distance between the points piston, in combinationwith-means for supplying the power to reciprocate the plston, includinga power driven crank pin adjacent the said opening in the end of saidcylinder and the means for translating the crank pin motionintoreciprocating motion of the piston consisting of. a link extendingfrom sad-pin through said opening and connected to the piston at a pointnear the head thereof, and means for maintaining a body of oil inbathing relation to said crank pin for splash feed lubrication of theparts'including the interiorof said tube.

'15. In a pressure pump apparatus, in

, combination, a pump comprising relatively movable pump elements and ametallic bellows secured to one of said pump elements at one end and tothe' other of said elements at the other end; the arrangement of partsbeing such that fluid pressures created by the pump apply pressure onthe exterior of the bellows. I

16. A pressure pump apparatus including a reciprocating piston forapplying pressure within the apparatus, means for operating it throughan opening to the exterior,

and means for sealing said piston against escape of fluid, consisting ofan imperforate, thin-walled, metal bellows tube, deeply corrugatedcircumferentially, secured airtight at one end to the rear of saidpiston with its intermediate 'portion surrounding the pistonreciprocating element, and its other end secured air tight about saidopening; and means affording fluid pressures which are much greater onthe exterior of the tube than on the interior thereof, for the purposeof keeping the. tube straight.

17.. A pressure pump apparatus including a reciprocating piston forapplying pressure within the apparatus, means for operating it throughan opening tothe exterior, and means for sealing said piston againstescape of fluid, consisting of an imperforate, thinwalled, metal bellowstube, deeply corrugated circumferentially, secured air-tight at one endto the rear of-said piston with,

its intermediate portion surrounding the piston reciprocating element,and 1ts other end secured air tight about said opening;-

and means applying fluid pressures of the pump on the exterior of thetube and approximately atmospheric pressures on the said passageconsisting of an imperforate,

thimwalled, metal bellows deeply corrugated circumferentially, havingone end sealed air tight around said passage and. the other endextending into-the cavity within said pressure chamber, a reciprocatingpiston to'the rear of which the inner end of said tube is secured airtight so that the piston forms an, air tight closure for said inner end,in combination with exterior driving means including a link extendingthrough said passageand into said bellows and connected to impartpredetermined limited movement to said movable piston; and cooperatingelements including the piston head on the inner side for utilizingwithin the chamber the relative'movements imparted thereto from theoutside thereof.

19.A chamber adapted to contain fluids under pressure sealed againstescape to the outer air, an opening affording a passage from theexterior into the chamber cavity; a closure for said passage consistingof an imperforate, thin walled, metal bellows deeply corrugatedcircumferentially, having one end sealed air tight around said passageand the other end extending into the cavity within said pressurechamber, and a relatively movable member to the rear side of which theinner end ofsaid tube is secured air tight and for which it forms an airtight closure, in combination with ex- "terior driving means extendingthrough contact with the outer surface of the bellows tube, operating tocushion and damp vibrations thereof.

In testimony whereof I have signed my name to this 1pecification.

ADFORD B. HOLMES,

